A welder at a factory in Edinburgh, in a file photo. REUTERS/David Moir

EDINBURGH (Reuters) - Almost one quarter of Scottish engineering and manufacturing firms have lost or are at risk of losing staff because of Britain’s decision to leave the European Union, a survey published on Wednesday found.

The poll by accountants Henderson Loggie also found almost three quarters of firms surveyed had problems recruiting staff with the right skills.

Immigration is one of the thorniest issues in Britain´s Brexit negotiations, as many of those who voted to leave were concerned about high levels of EU workers arriving. A leaked document last week showing Britain was considering measures to restrict immigration for all but the highest-skilled EU workers, raised hackles at British companies.

Immigration is particularly sensitive in Scotland where population decline, a source of concern for decades, had been reversed in recent years by young migrants arriving from the EU and settling.

The poll of 50 firms in Scotland and 460 across the UK carried out in June and July found 84 percent of firms expected production costs to continue to rise and 22 percent cited Brexit concerns as a barrier to growth.

“The sector continues to have difficulty recruiting staff with the relevant skills, the pressure on which is likely to increase as some businesses are at risk of losing staff due to Brexit,” said Gavin Black, partner at Henderson Loggie´s Manufacturing Group.

The survey found that 23 percent of businesses have lost or are at risk of losing staff as a result of Brexit, due to uncertainty over post-Brexit EU workers’ rights and a drop in the value of the pound. That compared with 20 percent in the UK as a whole.

A British trade survey conducted between March and May found nearly half of businesses operating in the food supply chain said EU workers were thinking about leaving because of uncertainty around Brexit.